Seven mutant maize genotypes with sweet corn backgrounds and 4 commercially grown sweet com cultivars were harvested from 18-45 days after pollination (DAP). The lipids were extracted, separated into major lipid fractions, transesterified and measured as methyl esters of palmitic (16:0), stearic (18:0), oleic (18:1), linoleic (18:2) and linolenic (18:3) acids by gas liquid chromatography (GLC). Neutral lipids had a low ratio of polyunsaturates to monounsaturates (1.7:1), i.e., linoleic and linolenic to oleic fatty acids. Glycolipids had the highest proportion of linoleic and linolenic acids. Phospholipids tended to be more saturated than other fractions because of their high proportion of palmitic acid. All fatty acids in the neutral lipid fraction increased on an absolute basis with advancing maturity. Fatty acids in the glycolipid and phospholipid fractions generally peaked at 28 DAP on a mg fatty acid/g corn wet weight basis and then decreased with increased maturity. The percentage of oleic acid in the glycolipid fraction doubled from 12-24 percent during the 18-45 DAP period. Experimental lines and commercial cultivars contained 18.4, 1.4, 21.5, 57.1 and 2.1 percent respectively of palmitic, stearic, oleic, linoleic and linolenic acid over the maturity ranges studied.
Received for publication March 19, 1974. Scientific Article No. A1979 Contribution No. 4916 of the Agricultural Experiment Station, Department of Horticulture.
Graduate Student and Professor, Department of Horticulture.